Facsimile system and apparatus



Oct. 2, 1951 Filed April 30, 1949 y M. ARTZT TAL FACSIMILE SYSTEM AND APPARATUS 5 sheds-sheet 1 TTORNEY Oct. 2, '1951 M. ARTzT x-:TAL

FACSIMILE SYSTEM AND APPARATUS s sheets-sheet 2 n Filed April so, 1949 Oct. 2, 1951 M. ARTzT- ETAL 2,559,548

FACSIMILE SYSTEM AND APPARATUS v Filed April 3o, 1949 s sheets-sheet s these two features combine to prevent light from any other source than the desired section of the filament from being introduced into the lens system. In other designs, where the light is shone onto a mirror and reiiected directly into the lens system contained in an optical barrel, it is possible for rays from undesired sources to be reiiected from the mirror onto the side walls of the barrel, and, even though the internal reiiections of this barrel are reduced by application ofv black matter to the inner surface, nevertheless, some light is reflected into the lens system in such manner as to decrease the sharpness of the scanning spot. This has the eiect of reducing the definition of the transmitted or received images and is especially noticeable where fine print is being transmitted.

In the type of facsimile machine wherein the source of illumination rotates with the scanner, it is customary to use what is called pre-focussed lamp, which is a light source having a base that is carefully set with respect to the filament so as to place the latter in the same position when one lamp is replaced by another. The need for such precision has been discussed above and because pre-focus lamps are expensive, attempts have been made to use ordinary lamps in such apparatus. However, such attempts have not been very successful because the filament has to be placed into the correct optical position for each lens and inasmuch as no special base is supplied, the tolerances normally encountered in manufacture, are too great to always allow the filament to be in the proper position when one lamp is substituted for another. To adjust the proper position of the lament in a facsimile machine having a rotating light source, is a tedious process of trial and error for the machine must be set into operation to check the proper position of the filament and then stopped while the lamp position is re-adjusted. As the lamp is mounted on the scanner and the latter is inside the transparent copy holder, it can be seen that it is diiiicuit to get it and therefore this trial and error process consumes a considerable amount of time and effort and is a very inefficient method of operation. Furthermore, it is possible that, if the filament is initially placed too far from the axis of rotation that the centrifugal forces discussed above will destroy the filament or move it out of line so as to make the lamp useless. In this invention, these diiculties are eliminated and the lamp is mounted on the carriage that moves slowly in an axial direction, thereby permitting adjustments of its position' to be made while the scanner is in operation, and it has been found feasible to make these adjustments within a period of less than one minute without the necessity of shutting the machine down.

It might at first be thought that the shadow cast by the filament supports would appear on the optical system and thereby change the intensity of the scanning spot. However, this is not the case because the common plane of the supports and the filament'passes through the axis of the cylinder at such an angle as to lie opposite the slot or groove through which the tongue of the carriage is projected.

The facsimile apparatus embodying the principles of this invention has another advantage over machines of the prior art, namely that both the photoelectric cell and the source of illumination are stationary with 'respect to the carriage thereby eliminating lthe necessity for slip rings. It was found; even-after experimentation with' various types of electrical brushes, that a fine dust caused by the wear of the brushes was deposited on the inner surface of the copy holder. The amount of light in the scanning spot naturally decreased as the machine was used until finally it was necessary to stop operations and clean the inside of the cylinder. The amount of cleaning necessary is greatly reduced if the brushes are eliminated, and in this invention no slip rings or brushes are required as both the phototube and the source of illumination are mounted on the carriage and do not rotate with the scanner.

In view of the foregoing discussion, it is one of the principal objects of this invention to provide a facsimile apparatus of the type wherein no slip rings are required.

A further object of the invention is to provide a facsimile apparatus of the type described in which the source of illumination for a given size of scanning assembly is a maximum.

A still further purpose of the invention is to provide an apparatus of the type described in which the optical path from the filament of the light source to the lens system in the scanner is a maximum.

Another object of the invention is to provide a facsimile machine of the type described in which it is not necessary to use pre-focussed lamps.

A still further object of the invention is to provide an apparatus of the type described in which the position of the filament can be readily adjusted while the machine is in operation.

Another object of the invention is to provide in a scanning assembly of the type described, an optical path for the light that passes through a double reflection so as to eliminate the introduction of undesired rays of light into the optical barrel supporting the lens system.

The method and apparatus by which these and other objects are achieved will be more readily understood from a consideration of the discussion given below in connection with the accompanying drawing in which:

Figure 1 shows a section view of the scanning assembly and the copy holder;

Figure 2 is a lcross section of Figure l taken at section line 2-2;

Figure 3 is a section taken at 3-3 of Figure l;

Figure 4 is a view of the side of the light cage adjacent to the scanner; and.

Figure 5 is a top view of the driving mechanism of the carriage and the scanning assembly.

The clearest understanding of the arrangement of the various parts of the facsimile apparatus that is the subject of this invention may be obtained from a consideration of Figure l, in which a transparent substantially cylindrical copy holder 2 is mounted between the end plates 4 and 6 that are in the form of annular rings, a carriage 8 being mounted so as to slide along the axis of the cylinder on a pair of guides l0, a tongue I5 protrudes into the inner part of the VIcylinder 2 through a slot or groove II in the side of the cylinder, which may be observed in Figures 2 and 3 so as to form a support for the scanner I2 which is mounted for rotation on the tongue I5 by means of bearings I4. A source of illumination I6 and a photosensitive pickup element I8 are mounted in appropriate positions nn the carriage so as to move with it, but neither vof them rotates with the scanner head I2.

In order to appreciate the advantages that inherently arisek from the use of a construction that the .Subiect or; this invention.. a detailed' is, of course, the axis of the copy Vholder 2. Light.

from this filament is prevented from escaping the cage 24 surrounding it except through aA sube stantially annular groove or slot 26 that may best be seen in Figure 4. A pickup mirror 28 is positioned on a bracket 30 that, is secured to the scanner I2 at such an angle as toA reect the image of the filament 28 through an opening 32 in the walls of the scanner to a reflecting mirror 34. The latter is so placed as to direct the image of the filament along the axis of the optical barrel 36 and through the lens system 38 which focusses the image of the filament on the inside surface of the copy. This optical path is indicated by the dotted line 39. Surrounding the optical barrel is parabolic reflector 46 that serves to pick up the spectral reflection from the sui-, face of the copy and direct theright so receivedv in a direction perpendicular to a reector 42 that is at 45 with respectl to the axis of rotation so as to direct the light in a direction parallel to, said axis. A nonrotating mirror 43 is mounted' on tongue 44 of cage '24 at an angle ofv 45 so that it reflects the beam of light in a direction that is again perpendicular to the axisv of rotation, and an opening 4t is provided in the tongue I that extends through the groove I I so that the light may fall upon the `photosensitive device I8 mounted in the base of the carriage. Therefore, as the pickup mirror A28 rotates, it is always in a symmetrical position relative to the filament and the annular groove 26. `Of course, when it passes the tongue I5, the light from the filament. is cut out, but this does not interfere with thescanning process as the scanning spot formed by scanning assembly I2V is not directed onto the copy placed upon the cylinder 2 but is directedat that instant into the groove II. Accordingly, if the filament supports 5.2 are in plane with the lament and this plane intersects the tongue I5, no shadows of thesel supports areintroduced into the optical system of the scanner.

The scanning spot ofv light `is actually an image of the iilarnent` 2.8 reduced. to an appropriate size and, therefore, the position of the lament with respect to, the pickup mirror 28r is critical. This being so, it is apparent that, when. a. lamp. ImistV be replaced, the means must be provided for properly positioning the filament, of the new.y lamp, This can be accomplished in two ways-.a one of which is to use a pre-focussed bulbwhich the relative position of the mounting base and the lilament, have been carefully adjusted for each bulb so as to take care of the tolerances encountered in manufacture, and the other method is to use an ordinary bulb andprovide means 54 for moving the filament` 20- and the bulb I6 up and down and back and forth. These ordinary bulbs are much cheaper than the pre--V focussed type and, inasmuch as the bulb ispnot, retailing with the scanner assembly, as is. the. case in other designs, it is a simple matter `to adiustits.nositicnwhile. the machine is inoperation. The end plate 58 can be removed and the adjustments 54 reached through the opening in the center of the annular ring 6.

In looking down theoptical axis of theV barrel 36 and the lenses 38, the image of the pick-up mirror 28 appears to be circular. In other words,

the image of the filament that is reected bythe mirror 28 is just large enough to ll the reflecting mirror t4 and the mirror 28 is of such size as to reiiect only the desired rays from the filament- 20. Thus, any rays coming from an undesired source having to pass through the opening 32- which is also just large enough to permit thev transmission of the desired amount oi;` light, and the double. reflection achieved bythzis. arrangement of the component parts pre'- vents light from undesired sources from being introduced into the optical barrel 36. Although the, internal reflections of the barrel are reduced by proper treatment, other systems introduce a certain amount of light to the lenses 38 so as to cause the scanning spot to becomediiused. For this reason, it is believed that a sharper definitioncan` be obtained by the apparatus herein disclosed,

To go into greater detail, a circular piece 6i) having an annular opening 62 and a lip 66 on which the reflector fill may rest, may be press t into the cylindrical opening 64 in the scanning head i 2. The optical barrel 38 has an inner optical barrel 35 that actually supports the lenses 36. and are aligned with the axis of the barrel 36.

and the lens system 38. An annular` cup 'I4 is clamped over the elliptical reilector 46 by a washer 88 that is screwed into the threads 82 in the inside of the opening 6.4; Means 8l are provided for adjusting the position of the pickup mirror 28;. Most of the details are also illustrated in Figures 2 and 3 and, in addition, there is shown two pairs of wheels 8d and 85 respectively that ride on the guide numbers 1.8 so as to permit free motion of the carriage along the axis of the cylinder 2. A base 8l in which the guide members Il]A are mounted serves asl a support for the whole lmachine and the cylinders 2 are mounted means of clamps 88 `and screws SI] to thel 'a-nges182 that form the opening I I throughwhich- -the tongue I5 of the carriage is inserted.

`Figure 5: is an assembly drawing of a facsimile machine embodying the principles of the invention in which there is shown a receiver for duplieating the master copy that is placed on thetransparent drum 2. Of course, the signals picked upuf-rom the photoelectric cell I8 may be transmitted' to a remote receiver in addition to being suppliedato the duplicator, but the latter is ineluded for the purposes of explaining the overall operation. Furthermore, a duplicating machine located at the transmitter makes it possible to monitor thev quality of the transmitted image. Broadlyespeaking, the right hand portion of the drawing is a top view of the scanning assembly shown-iin Figure 1 withy the cage 24, the scanner head-I2; and the support I3 for the bearings I4'- shown-inA right to left order. To the left of this transmitter is a reproducingl drum S4 having a helical electrical contact 96 and a printer bar 98 which-functiontopass an amount of current proportional: tos thel signaldeveloped in the photoelectric cell Ifthrough a sensitized paper that lies between them'. The driving motor |681 is coupled to the shaft |02 which is supported by the shaft |08 is made small enough to fit inside the square hollow shaft H0, and a square coupling member H2, that is small enough to slide freely within. the shaft H0, is secured to the end of the shaft |08.

As the shaft |02 turns, a worm drive |14, cut on its outside diameter, meshes with a gear` ||6 which is secured to the shaft |B so as to rotate a small drum |20 which is mounted upon it. As-

the drum |20 rotates, it winds up a line |22 which, because it is passed around a pulley |24 and secured to the carriage 8, moves the latter along the axis of the cylinder 2 in a direction away from the reproducing drum 94. The shaft H is comprised of 2 parts, one end riding in a bearing |26 and the other in a bearing |28 that are operatively joined together by any suitable clutch mechanism |30 which, for purposes of illustration, is shown as a toothed dog. The coil spring |32 wound around the shaft ||8 forces the clutch into contact but may be released by a forked lever |34 pivoted at point |36 so that its forked end rides in the circular groove |38 formed by the collars |40. When the clutch |30 is released, a spring tension drum |40 winds up cord |42 so as to return the carriage I8 to the left in preparation for a succeeding scanning operation.

Various alterations may be made in the present invention without departing from the spirit and scope thereof, and it is desired that any and all such alterations be considered within the purview ofthe present invention as defined by the hereinafter appended claims.

Having described the invention, what is claimed and desired to be secured by Letters Patent is the following:

1. A facsimile device comprising a light transmitter copy holder, a carriage, means for guiding said carriage longitudinally of said copy holder, a rotary scanner mounted on said carriage having an optical system for projecting a beam of light onto said copy holder, the axis of rotation of said scanner coinciding with the axis of said copy holder, means for rotating said scanner, means for imparting longitudinal motion along said guiding means to said carriage in accordance with the rotation of said scanner, a source of illumination mounted so as to be stationary with respect to said carriage, and a pickup mirror mounted on said scanner so as to intercept light from said source during a predetermined portion of a revolution and direct it into the optical system of said scanner.

2. A facsimile apparatus comprising a transparent copy holder, a rotary scanning head, a carriage for supporting said scanning head for rotation about the axis of said copy holder, means for rotating said scanning head and means for moving said carriage along the axis of said copy holder, a light source mounted on said carriage, a use surrounding said light source, a substantially annular opening in one end of said cage, an overhanging circular use mounted on the same edge of the cage as the annular opening, said. lip

being concentric with the axis of said copy holder, a ring mounted on said scanning head, said ring being concentric with said copy holder, said ring extending inside said lip so as to prevent the' escape of light therebetween, and a pickup mirror mounted on the inside of said ring so as to inter-v cept light from said source through said groove during a predetermined portion of a revolution of the scanning head. y

3. A facsimile scanner comprising a cylindrical light transmitting copy holder, a rotatable scanning head, a carriage' member for' supporting said scanning head adapted to pass through a longitudinal slot in said copy holder, said scanning head being rotatable about the axis of said cylinder and axially movable with said carriage, a

light source mounted on said carriage so as to be.

arranged to direct light reflected at the surfacev of the copy holdery in a direction perpendicularr to the axis thereof, an axial opening in the end of said scanning head, amirror for reflecting the light along the axis of the copy holder and through said opening, a reflector mounted on said carriage, said reflector being so positioned that it directs the light received from said mirror in a direction perpendicular to the axis of the copy holder, and a light sensitive device mounted on said carriage in such position as to bel activated bythe light refected by said reiector.

4. A facsimile scanner comprising a cylindrical light transmitting copy holder, a scanning device, a carriage member for supporting said scanningy device adapted to pass through a longitudinal slot in said copy holder, said scanning device being concentric with said copy holder and axiallymovable with said carriage, a light source comprised of a filament coinciding with the axis of said copy holder, supports for said filament, said supports being in a plane passing through said axis and in the same radial position with respect thereto as said slot, optical means for producinga scanning light spot on a surface of said copy holder and arranged to direct the reflected light from subject matter in contact with said surface so that it passes out of said scanning device along saidV common axis, and a phototube mounted on said carriage to receive said reflected light.

MAURICE ARTZT.

CHARLES J. YOUNG.

REFERENCES CITED The following references are of record in the file of this patent:

i 599,748 Great Britain Mar. 19, 1940 

